Clamp



FIG. 1 is a perspective view of a clamp showing my new design with the clamping rod shown in broken lines for illustrative purposes only;

FIG. 2 is another perspective view thereof;

FIG. 3 is a side elevational view thereof;

FIG. 4 is a top plan view thereof;

FIG. 5 is a bottom plan view thereof. 

The ornamental design for a clamp, as shown and described. 